[RE-wrenches] Concrete tight versus raintight

William Miller william at millersolar.com
Thu Jan 16 11:54:05 PST 2014


Friends:

 

We used some Bridgeport fittings yesterday.  My foreman reports the
following:

 

The new blue rain tite connectors have a prob. The connectors have a plastic
gasket/ring that seals between the connector body and the box. It is
impossible to tighten the con to box without destroying the ring or having a
slightly loose con/box connection. A loose connection means poor bonding. 

 

I would add that any looseness of these fittings can contribute to
mechanical failure of conduit runs.  We rely on code compliant strapping
*and* secure tightening of fittings to keep a conduit assembly secure and in
place for years to come.  It looks like we need to find a fitting with
firmer washers.  The Arlington NMLT fittings have yellow washers that are
pretty rigid.  I will rob one and try it on the Bridgeports.  We bought a
quantity of the EMT fittings and I don't want to have to replace them.

 

William

 

 

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of August Goers
Sent: Thursday, January 16, 2014 8:00 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] Concrete tight versus raintight

 

Hi William,

 

About 5 years ago this became a big issue up in San Francisco and we had to
learn the hard way. We used to just go buy outdoor EMT fittings and we were
okay, then the inspectors started requiring fittings that say raintight or
wet location (often stamped "wetloc") on them. I don't know for certain, but
I believe it might have been a clarification added in the 2008 NEC at the
time. See "NEC 358.42 Couplings and Connectors. Couplings and connectors
used with EMT shall be made up tight. Where buried in masonry or concrete,
they shall be concretetight type. Where installed in wet locations, they
shall comply with 314.15."

 

If you go over to NEC 314.15 they mention that fittings installed in wet
locations shall be listed for use in wet locations. 

 

So, you just need to make sure that the fittings you get are listed for the
correct purpose. I have seen both concretetight and wetloc type. As someone
else mentioned, most of the wetloc fittings have a plastic sealing ring in
them and many or blue colored.

 

Best,

 

August

Luminalt

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of William
Miller
Sent: Wednesday, January 15, 2014 10:32 PM
To: RE-wrenches
Subject: [RE-wrenches] Concrete tight versus raintight

 

Friends:

 

It appears I may have a whole in my education.  I thought all EMT
compression fittings were alike.  It appears that I have been using
"concrete tight" fittings where I should have been using "raintight"
fittings.  Did they use to be the same item?  I did a web search on the
differences and came up empty.  I want to be informed in this area and
appreciate any knowledge.

 

William Miller

 

 

Gradient Cap

Lic 773985

millersolar.com <http://www.millersolar.com/> 

805-438-5600

 

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